The Juniper SRX Services Gateway VPN must disable split-tunneling for remote clients VPNs.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-214695	JUSX-VN-000028	SV-214695r383596_rule		Medium

Description
Split tunneling would in effect allow unauthorized external connections, making the system more vulnerable to attack and to exfiltration of organizational information. A VPN hardware or software client with split tunneling enabled provides an unsecured backdoor to the enclave from the Internet. With split tunneling enabled, a remote client has access to the Internet while at the same time has established a secured path to the enclave via an IPsec tunnel. A remote client connected to the Internet that has been compromised by an attacker in the Internet, provides an attack base to the enclave’s private network via the IPsec tunnel. Hence, it is imperative that the VPN gateway enforces a no split-tunneling policy to all remote clients. Traffic to the protected resource will go through the specified dynamic VPN tunnel and will therefore be protected by the Juniper SRX firewall’s security policies.

Description

Split tunneling would in effect allow unauthorized external connections, making the system more vulnerable to attack and to exfiltration of organizational information. A VPN hardware or software client with split tunneling enabled provides an unsecured backdoor to the enclave from the Internet. With split tunneling enabled, a remote client has access to the Internet while at the same time has established a secured path to the enclave via an IPsec tunnel. A remote client connected to the Internet that has been compromised by an attacker in the Internet, provides an attack base to the enclave’s private network via the IPsec tunnel. Hence, it is imperative that the VPN gateway enforces a no split-tunneling policy to all remote clients. Traffic to the protected resource will go through the specified dynamic VPN tunnel and will therefore be protected by the Juniper SRX firewall’s security policies.

STIG	Date
Juniper SRX Services Gateway VPN Security Technical Implementation Guide	2021-03-25

Details

Check Text ( C-15896r297672_chk )
Verify split-tunneling is disabled. [edit] show security dynamic-vpn access-profile If split-tunneling is not disabled, this is a finding.

Fix Text (F-15894r297673_fix)
Configure the VPN tunnel to control what is sent out in clear text. The “remote-protected-resources” command defines what is routed through the tunnel. The “remote-exceptions” command defines what traffic is sent out in clear text. The following is an example. [edit] set security dynamic-vpn access-profile set security dynamic-vpn clients all ipsec-vpn set security dynamic-vpn clients all remote-protected-resources set security dynamic-vpn clients all remote-exceptions 0.0.0.0/0

Fix Text (F-15894r297673_fix)

Configure the VPN tunnel to control what is sent out in clear text. The “remote-protected-resources” command defines what is routed through the tunnel. The “remote-exceptions” command defines what traffic is sent out in clear text. The following is an example.

[edit]
set security dynamic-vpn access-profile
set security dynamic-vpn clients all ipsec-vpn
set security dynamic-vpn clients all remote-protected-resources
set security dynamic-vpn clients all remote-exceptions 0.0.0.0/0